This disclosure relates to gas turbine engines, and more particularly to systems and methods for alternating starter use during multi-engine motoring of gas turbine engines.
Gas turbine engines are used in numerous applications, one of which is for providing thrust to an airplane. When the gas turbine engine of an airplane has been shut off for example, after an airplane has landed at an airport, the engine is hot and due to heat rise, the upper portions of the engine will be hotter than lower portions of the engine. When this occurs thermal expansion may cause deflection of components of the engine which may result in a “bowed rotor” condition. If a gas turbine engine is in such a bowed rotor condition it is undesirable to restart or start the engine.
One approach to mitigating a bowed rotor condition is to use a starter system to drive rotation of a spool within the engine for an extended period of time at a speed below which a resonance occurs (i.e., a critical speed or frequency) that may lead to damage when a sufficiently large bowed rotor condition is present. Motoring is typically performed separately for each engine at different times, which extends the total start time for a multi-engine aircraft.